Biopsies from breast cancer patients treated with adjuvant RT may exhibit upregulated gene expression for collagen types I and III and TGF-β1 up to 20 years after RT.29 In porcine and mouse skin, radiation-induced elevated TGF-β1 levels remain high for up to 12 months after radiation and are localized to myofibroblasts, endothelial cells, and the collagen matrix.15,30. This evidence concerns the gene TGFB1 and breast cancer.